Epoxy Resin Suggestions

Ben M

Ben M

Active member
I'm just getting my first build started and won't arrive at the fiberglass stage for quite some time, but wanted to go ahead get some recommendations on what resin to use. 3M has an all-purpose resin at big box stores for $35-ish per gallon. But most other resins are a lot more expensive than that. Are they worth it? Is the 3M all-purpose ok to use?
 
Ben,

Wait for Mark W to chime in, he is our resident expert when it comes to 3M products. (absolutely true, not joking on this)

My guess is that the epoxy you are referring to is poly based and might not be the easiest or best to work with for a entire build.
 
most your box store and farm store resins are poly and are not the best material to use over plywood. Their properties change as they age and the materials will delaminate from the wood. Not to mention that you need to ventilate your shop or use the stuff outside. Their best use is for making a solid glass hull.

For a wood boat it is best to use a high solids epoxy resin like that sold by US composites, RAKA, WEST System, System Three, etc. They are more expensive, but they work best with plywood and solid wood. US Composites and RAKA are shockingly cheap compared to the other epoxy makers, and I have found that the end product (painted epoxy coated marine plywood) is just as comparable in use as something made with WEST epoxy.

There have been many boats built with poly resin and if you plan on treating the boat with lots of care and keep it out of the sun and dry it will last for many years. It may not make it to your kids or grand kids though before needing to be rebuilt.

If you are going to store your boat outside in the elements and only want to build it one time, then use an epoxy resin.
 
I think what Ray is saying is that epoxy is glue and resin.... Polyester, vinylester are not glue, but are resins. They make the fiberglass stay in shape, but not hold it to the wood. Epoxy makes the structure more of a monolithic structure. Ray is correct. Although epoxies are a bit different one to the next for backyard building find the best deal and then familiarize yourself with the properties. all have different pot lifes, viscosities... some are better for wetting out fiberglass others are for wood to wood glue up without fillers. Keep in mind WEST was the pioneer and they have great customer service. With that said I used two gallons of systems three today. I have large goo grinders for making large batches. The ratio of these grinders is 2:1. WEST is 5:2 I think. Anyway Good luck be safe with the stuff.
Frank
 
There are only a handful of bulk resin manufacturers in this country. Most of the name brands we are used to, purchase these bulk resins and alter it to suit their performance statistics. My shop uses 10-15 drums of epoxy a year. The modified high-performance resins are very expensive, less labor intensive in a production environment. If I were just making a boat for myself (which I just did) I would use the generic resin for its dollar value. We are paying around 35.00 per gallon for the generic resin, much more for the name brands. Find a shop using big quantities of epoxy, bring some jugs and buy a few gallons. The generics are usually slow curing, quite forgiving. A simple two-to-one mix and clean up with soap and water. The designer brands are a bit more temperamental, quicker curing, and cost a fortune. You will be amazed at how much will probaly go off in the pot! Like the other guys said, forget the polyester. And what you don't use, put in the freezer before it kicks, save it for later or tomorrow. The generics can be thickened (Cabosil) or thinned (Denatured alcohol). Yes, West was the pioneer supplier for do-ti-yourselfers, but Reichold, Shell, Celanese were manufacturing epoxy resin for industry when the Gugeon Bros. (West) were in diapers.

By the way, use rubber gloves with epoxy. Resin itself is pretty inert. It's the hardener that really tears up some people's skin!
 
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